• Re: Real Number & Restoring Interpretation of Calculus

    From Mikko@21:1/5 to wij on Sun Mar 24 18:13:19 2024
    On 2024-03-24 14:59:52 +0000, wij said:

    Note: This definition implies that repeating decimals are irrational number.

    This contradicts the definition that an irrationa number is not rational.

    Let's list a common magic proof in the way as a brief explanation:
    (1) x= 0.999...
    (2) 10x= 9+x // 10x= 9.999...
    (3) 9x=9
    (4) x=1
    Ans: There is no axiom or theorem to prove (1) => (2).

    A theory of numbers should have enough axioms to determine what
    the sum or product of any two numbers is.

    --
    Mikko

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  • From immibis@21:1/5 to wij on Sun Mar 24 23:35:10 2024
    On 24/03/24 15:59, wij wrote:
    The purpose this text is for establishing the bases for computational algorithm.
    This file https://sourceforge.net/projects/cscall/files/MisFiles/RealNumber-en.txt/download
    may be updated anytime.

    +-------------+
    | Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the
    string may contain a plus/minus sign or a point:

    <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ]
    <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>]
    <dstr2>::= { 0, <nzd> } <nzd>
    <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9) // 'digit' varys depending on n-ary

    Two n-ary fixed-point number x,y are equal iff their form as mentioned above
    are identical.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point number. The string
    of digits of x may be infinitely long }

    Note: This definition implies that repeating decimals are irrational number.

    So the RATIO of 1 and 7 isn't RATIOnal?

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  • From immibis@21:1/5 to wij on Mon Mar 25 01:09:21 2024
    On 25/03/24 00:05, wij wrote:
    On Sun, 2024-03-24 at 23:35 +0100, immibis wrote:
    On 24/03/24 15:59, wij wrote:
    The purpose this text is for establishing the bases for computational algorithm.
    This file https://sourceforge.net/projects/cscall/files/MisFiles/RealNumber-en.txt/download
    may be updated anytime.

    +-------------+
    Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the >>>     string may contain a plus/minus sign or a point:

          <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ]
          <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>]
          <dstr2>::= { 0, <nzd> } <nzd>
          <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9)  // 'digit' varys depending on n-ary

        Two n-ary fixed-point number x,y are equal iff their form as mentioned above
        are identical.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point number. The string
        of digits of x may be infinitely long }

        Note: This definition implies that repeating decimals are irrational number.

    So the RATIO of 1 and 7 isn't RATIOnal?

    All rationals p/q are representable by q-ary fixed-point number.


    0.99999... is representable by the following 10-ary fixed-point number: 1.0.

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  • From immibis@21:1/5 to wij on Mon Mar 25 01:59:22 2024
    On 25/03/24 01:53, wij wrote:
    On Mon, 2024-03-25 at 01:09 +0100, immibis wrote:
    On 25/03/24 00:05, wij wrote:
    On Sun, 2024-03-24 at 23:35 +0100, immibis wrote:
    On 24/03/24 15:59, wij wrote:
    The purpose this text is for establishing the bases for computational algorithm.
    This file https://sourceforge.net/projects/cscall/files/MisFiles/RealNumber-en.txt/download
    may be updated anytime.

    +-------------+
    Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the >>>>>      string may contain a plus/minus sign or a point:

           <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ]
           <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>]
           <dstr2>::= { 0, <nzd> } <nzd>
           <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9)  // 'digit' varys depending on n-ary

         Two n-ary fixed-point number x,y are equal iff their form as mentioned above
         are identical.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point number. The string
         of digits of x may be infinitely long }

         Note: This definition implies that repeating decimals are irrational number.

    So the RATIO of 1 and 7 isn't RATIOnal?

    All rationals p/q are representable by q-ary fixed-point number.


    0.99999... is representable by the following 10-ary fixed-point number: 1.0.

    How?

    By the proof you already showed and rejected, they are two ways of
    writing the same number. At least in the real numbers. If you make up a
    new number system, it won't be the same as the real numbers and you
    shouldn't call it the real numbers.

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  • From immibis@21:1/5 to wij on Mon Mar 25 03:29:43 2024
    On 25/03/24 02:31, wij wrote:
    On Mon, 2024-03-25 at 01:59 +0100, immibis wrote:
    On 25/03/24 01:53, wij wrote:
    On Mon, 2024-03-25 at 01:09 +0100, immibis wrote:
    On 25/03/24 00:05, wij wrote:
    On Sun, 2024-03-24 at 23:35 +0100, immibis wrote:
    On 24/03/24 15:59, wij wrote:
    The purpose this text is for establishing the bases for computational algorithm.
    This file
    https://sourceforge.net/projects/cscall/files/MisFiles/RealNumber-en.txt/download
    may be updated anytime.

    +-------------+
    Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the
          string may contain a plus/minus sign or a point:

            <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ] >>>>>>>         <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>]
            <dstr2>::= { 0, <nzd> } <nzd>
            <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9)  // 'digit' varys depending on n-ary

          Two n-ary fixed-point number x,y are equal iff their form as mentioned above
          are identical.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point number. The string
          of digits of x may be infinitely long }

          Note: This definition implies that repeating decimals are irrational number.

    So the RATIO of 1 and 7 isn't RATIOnal?

    All rationals p/q are representable by q-ary fixed-point number.


    0.99999... is representable by the following 10-ary fixed-point number: 1.0.

    How?

    By the proof you already showed and rejected, they are two ways of
    writing the same number. At least in the real numbers. If you make up a
    new number system, it won't be the same as the real numbers and you
    shouldn't call it the real numbers.

    It not 'make-up', instead, your math. theory is fabricated, in way worst than mine, at least.

    If you like to stick to the theory that the universe revolves around the earth, that is fine.
    One thing to be sure, such theory won't survive.

    If two real numbers defined by Dedekind cuts are different, there is a
    number in between them. This is obvious from the Dedekind cut
    definition. If you invent a different system, you can do that but it's a different system.

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  • From Fred. Zwarts@21:1/5 to All on Mon Mar 25 09:47:34 2024
    Op 25.mrt.2024 om 04:11 schreef wij:
    On Mon, 2024-03-25 at 03:29 +0100, immibis wrote:
    On 25/03/24 02:31, wij wrote:
    On Mon, 2024-03-25 at 01:59 +0100, immibis wrote:
    On 25/03/24 01:53, wij wrote:
    On Mon, 2024-03-25 at 01:09 +0100, immibis wrote:
    On 25/03/24 00:05, wij wrote:
    On Sun, 2024-03-24 at 23:35 +0100, immibis wrote:
    On 24/03/24 15:59, wij wrote:
    The purpose this text is for establishing the bases for computational algorithm.
    This file
    https://sourceforge.net/projects/cscall/files/MisFiles/RealNumber-en.txt/download
    may be updated anytime.

    +-------------+
    Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the
           string may contain a plus/minus sign or a point: >>>>>>>>>
             <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ] >>>>>>>>>          <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>]
             <dstr2>::= { 0, <nzd> } <nzd>
             <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9)  // 'digit' varys depending on n-ary

           Two n-ary fixed-point number x,y are equal iff their form as mentioned above
           are identical.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point number. The string
           of digits of x may be infinitely long }

           Note: This definition implies that repeating decimals are irrational number.

    So the RATIO of 1 and 7 isn't RATIOnal?

    All rationals p/q are representable by q-ary fixed-point number. >>>>>>>

    0.99999... is representable by the following 10-ary fixed-point number: 1.0.

    How?

    By the proof you already showed and rejected, they are two ways of
    writing the same number. At least in the real numbers. If you make up a >>>> new number system, it won't be the same as the real numbers and you
    shouldn't call it the real numbers.

    It not 'make-up', instead, your math. theory is fabricated, in way worst than mine, at least.

    If you like to stick to the theory that the universe revolves around the earth, that is fine.
    One thing to be sure, such theory won't survive.

    If two real numbers defined by Dedekind cuts are different, there is a
    number in between them. This is obvious from the Dedekind cut
    definition. If you invent a different system, you can do that but it's a
    different system.


    Let's say yes (if you'd like me to put this way), I am inventing a system to replace your obsolete
    system.

    A system becomes obsolete only if a new system has been worked out and
    it is proved to have an advantage. As long as a new system is being
    invented and no advantage has been proved, the old system is not obsolete.

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  • From Fred. Zwarts@21:1/5 to All on Mon Mar 25 09:43:32 2024
    Op 25.mrt.2024 om 01:53 schreef wij:
    On Mon, 2024-03-25 at 01:09 +0100, immibis wrote:
    On 25/03/24 00:05, wij wrote:
    On Sun, 2024-03-24 at 23:35 +0100, immibis wrote:
    On 24/03/24 15:59, wij wrote:
    The purpose this text is for establishing the bases for computational algorithm.
    This file https://sourceforge.net/projects/cscall/files/MisFiles/RealNumber-en.txt/download
    may be updated anytime.

    +-------------+
    Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the >>>>>      string may contain a plus/minus sign or a point:

           <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ]
           <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>]
           <dstr2>::= { 0, <nzd> } <nzd>
           <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9)  // 'digit' varys depending on n-ary

         Two n-ary fixed-point number x,y are equal iff their form as mentioned above
         are identical.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point number. The string
         of digits of x may be infinitely long }

         Note: This definition implies that repeating decimals are irrational number.

    So the RATIO of 1 and 7 isn't RATIOnal?

    All rationals p/q are representable by q-ary fixed-point number.


    0.99999... is representable by the following 10-ary fixed-point number: 1.0.

    How?

    1.0 = 3*(1/3) = 3*0.33333... = 0.99999...

    If not (if there is a difference), which number expresses the difference between 1.0 and 0.99999... ?

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  • From Fred. Zwarts@21:1/5 to All on Mon Mar 25 10:55:45 2024
    Op 25.mrt.2024 om 10:11 schreef wij:
    On Mon, 2024-03-25 at 09:43 +0100, Fred. Zwarts wrote:
    Op 25.mrt.2024 om 01:53 schreef wij:
    On Mon, 2024-03-25 at 01:09 +0100, immibis wrote:
    On 25/03/24 00:05, wij wrote:
    On Sun, 2024-03-24 at 23:35 +0100, immibis wrote:
    On 24/03/24 15:59, wij wrote:
    The purpose this text is for establishing the bases for computational algorithm.
    This file
    https://sourceforge.net/projects/cscall/files/MisFiles/RealNumber-en.txt/download
    may be updated anytime.

    +-------------+
    Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the
          string may contain a plus/minus sign or a point:

            <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ] >>>>>>>         <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>]
            <dstr2>::= { 0, <nzd> } <nzd>
            <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9)  // 'digit' varys depending on n-ary

          Two n-ary fixed-point number x,y are equal iff their form as mentioned above
          are identical.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point number. The string
          of digits of x may be infinitely long }

          Note: This definition implies that repeating decimals are irrational number.

    So the RATIO of 1 and 7 isn't RATIOnal?

    All rationals p/q are representable by q-ary fixed-point number.


    0.99999... is representable by the following 10-ary fixed-point number: 1.0.

    How?

    1.0 = 3*(1/3) = 3*0.33333... = 0.99999...

    What is that? Refutation by assertion?

    If not (if there is a difference), which number expresses the difference
    between 1.0 and 0.99999... ?

    Let a=0.999..., b=1, c=(a+b)/2, c is the number between a and b. (dense property)


    I did not ask about a number between a and b, but about the difference
    between a and b. How do you write a-b? Is that -0.00000...? Do you think
    it is not equal to 0.0?

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  • From Mikko@21:1/5 to Fred. Zwarts on Mon Mar 25 11:16:35 2024
    On 2024-03-25 08:47:34 +0000, Fred. Zwarts said:

    Op 25.mrt.2024 om 04:11 schreef wij:
    On Mon, 2024-03-25 at 03:29 +0100, immibis wrote:
    On 25/03/24 02:31, wij wrote:
    On Mon, 2024-03-25 at 01:59 +0100, immibis wrote:
    On 25/03/24 01:53, wij wrote:
    On Mon, 2024-03-25 at 01:09 +0100, immibis wrote:
    On 25/03/24 00:05, wij wrote:
    On Sun, 2024-03-24 at 23:35 +0100, immibis wrote:
    On 24/03/24 15:59, wij wrote:
    The purpose this text is for establishing the bases for computational
    algorithm.
    This file
    https://sourceforge.net/projects/cscall/files/MisFiles/RealNumber-en.txt/download

    may be updated anytime.

    +-------------+
    Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the
           string may contain a plus/minus sign or a point: >>>>>>>>>>
             <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ] >>>>>>>>>>          <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>]
             <dstr2>::= { 0, <nzd> } <nzd>
             <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9)  // 'digit' varys
    depending on n-ary

           Two n-ary fixed-point number x,y are equal iff their form as
    mentioned above
           are identical.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point number. The string
           of digits of x may be infinitely long }

           Note: This definition implies that repeating decimals are
    irrational number.

    So the RATIO of 1 and 7 isn't RATIOnal?

    All rationals p/q are representable by q-ary fixed-point number. >>>>>>>>

    0.99999... is representable by the following 10-ary fixed-point number: 1.0.

    How?

    By the proof you already showed and rejected, they are two ways of
    writing the same number. At least in the real numbers. If you make up a >>>>> new number system, it won't be the same as the real numbers and you
    shouldn't call it the real numbers.

    It not 'make-up', instead, your math. theory is fabricated, in way
    worst than mine, at least.

    If you like to stick to the theory that the universe revolves around
    the earth, that is fine.
    One thing to be sure, such theory won't survive.

    If two real numbers defined by Dedekind cuts are different, there is a
    number in between them. This is obvious from the Dedekind cut
    definition. If you invent a different system, you can do that but it's a >>> different system.


    Let's say yes (if you'd like me to put this way), I am inventing a
    system to replace your obsolete
    system.

    A system becomes obsolete only if a new system has been worked out and
    it is proved to have an advantage.

    And even then not always. What makes the new system better for some
    purposes may make it worse for other purposes. For example, Riemannian
    geometry covers everything Euclidean geometry covers and more but
    Euclidean geometry is still used as it is easier to use where it
    can be used.

    --
    Mikko

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  • From Andy Walker@21:1/5 to Fred. Zwarts on Mon Mar 25 10:08:53 2024
    On 25/03/2024 08:43, Fred. Zwarts wrote:
    1.0 = 3*(1/3) = 3*0.33333... = 0.99999...

    Just to point out that all such "visual" proofs are flawed.
    We normally multiply from the right, with the rules about "carries".
    With infinite strings, we have to multiply from the left, meaning
    that at any given stage, we have a range of possible answers. Thus
    3 * 0.3xyz... lies between 0.90 and 1.02, and we can't write down
    the start of the answer until we inspect x; if x < 3, then the
    answer starts 0.9; if x > 3, it starts 1.0; sadly, if x = 3, then
    we have made no progress until we inspect y and then z. If they are
    all 3's, then we continually have to defer starting the answer, and
    we never find out whether 3 * 0.333... is 0.999... or 1.000.... I
    suspect that most people who are happy with the above would be less
    happy with "1.0 = 7*(1/7) = 7*0.1428561428... = 0.99999..." where you
    clearly have to worry about the carries.

    [Of course, there are satisfactory proofs that in the reals
    0.999... = 1 using standard results about limits. But these are much
    harder to explain to non-mathematicians. Inevitably, they depend on
    the Archimedean axiom, which is not (at least in the UK) routinely
    taught to children as they learn about numbers.]

    If not (if there is a difference), which number expresses the
    difference between 1.0 and 0.99999... ?

    In [for example] the surreals and the hyperreals, there are
    numbers that are strictly less than 1 and strictly greater than any
    member of 0.9, 0.99, 0.999, .... Some such system of numbers would
    surely meet Wij's needs better than a half-baked attempt to describe
    an incoherent extension to the reals.

    [Wiki on both of the above is a decent introduction once you
    are past the first couple of paragraphs; but I suspect that most
    Wij-alikes give up on reading "In mathematics, the surreal number
    system is a totally ordered proper class ...".]

    --
    Andy Walker, Nottingham.
    Andy's music pages: www.cuboid.me.uk/andy/Music
    Composer of the day: www.cuboid.me.uk/andy/Music/Composers/Bizet

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  • From Ben Bacarisse@21:1/5 to wij on Mon Mar 25 10:24:06 2024
    wij <wyniijj5@gmail.com> writes:

    +-------------+
    | Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the
    string may contain a plus/minus sign or a point:

    <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ]
    <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>]
    <dstr2>::= { 0, <nzd> } <nzd>
    <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9) // 'digit' varys depending
    on n-ary

    So neither 0 nor 10 are Fixed_point numbers. OK. That's going to limit
    the usefulness of these numbers.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point
    number. The string of digits of x may be infinitely long }

    That's ill-defined as there are two {0, <nzd>} parts in the grammar. I
    think you intended only one of them to be permitted to be not finite.

    (And as has been pointed out, this is not a model of set to the real
    numbers. You need to choose a different name.)

    As usual, you don't really care about the details, do you? It's all
    about looking technical rather than being precise.

    --
    Ben.

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  • From Richard Damon@21:1/5 to wij on Mon Mar 25 07:14:38 2024
    On 3/25/24 5:11 AM, wij wrote:
    On Mon, 2024-03-25 at 09:43 +0100, Fred. Zwarts wrote:
    Op 25.mrt.2024 om 01:53 schreef wij:
    On Mon, 2024-03-25 at 01:09 +0100, immibis wrote:
    On 25/03/24 00:05, wij wrote:
    On Sun, 2024-03-24 at 23:35 +0100, immibis wrote:
    On 24/03/24 15:59, wij wrote:
    The purpose this text is for establishing the bases for computational algorithm.
    This file
    https://sourceforge.net/projects/cscall/files/MisFiles/RealNumber-en.txt/download
    may be updated anytime.

    +-------------+
    Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the
          string may contain a plus/minus sign or a point:

            <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ] >>>>>>>         <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>]
            <dstr2>::= { 0, <nzd> } <nzd>
            <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9)  // 'digit' varys depending on n-ary

          Two n-ary fixed-point number x,y are equal iff their form as mentioned above
          are identical.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point number. The string
          of digits of x may be infinitely long }

          Note: This definition implies that repeating decimals are irrational number.

    So the RATIO of 1 and 7 isn't RATIOnal?

    All rationals p/q are representable by q-ary fixed-point number.


    0.99999... is representable by the following 10-ary fixed-point number: 1.0.

    How?

    1.0 = 3*(1/3) = 3*0.33333... = 0.99999...

    What is that? Refutation by assertion?

    If not (if there is a difference), which number expresses the difference
    between 1.0 and 0.99999... ?

    Let a=0.999..., b=1, c=(a+b)/2, c is the number between a and b. (dense property)


    But the density property requires a and b to be DIFFERENT numbers before
    it asserts that there is a number between them, otherwise c is just the
    same number as a and b.

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  • From Andy Walker@21:1/5 to wij on Mon Mar 25 12:49:04 2024
    On 25/03/2024 12:04, wij wrote:
    IMO, these all boil down to the question "what is number?".

    Yes, but you persist in calling your answer "real number".
    Sorry, but that concept is taken. Either "Wij-number" and "real
    number" are the same [in which case a lot of what you say is plain
    wrong, as wrong as a cartload of wrong things], or they differ, in
    which case you need to find another name [and "surreal", "hyperreal", "superreal" and others are also already taken].

    I find it better
    (so far) to define 'number' on symbols and the associated ops.
    Because I feel computation (TM, algorithm,program,..) can and should be a large
    part of the basics of mathematics.

    Sure, but that has been true "forever", and has been largely
    formalised and analysed [NA, symbolic computation, ...] for several
    decades. I don't see anything new or even interesting in what you
    have been writing.

    E.g. I feel infinity may be nothing but a
    manifest of procedural loop.

    Lots of clever people have been grappling with infinities and infinitesimals over the past 2500 or so years. You are going to have
    to work a lot harder to produce anything interesting that evaded
    Archimedes, Newton, Euler, ....

    [Ben:]
    As usual, you don't really care about the details, do you?  It's all
    about looking technical rather than being precise.
    “Premature optimization is the root of all evil”

    Yes, but arm-waving is little better.

    --
    Andy Walker, Nottingham.
    Andy's music pages: www.cuboid.me.uk/andy/Music
    Composer of the day: www.cuboid.me.uk/andy/Music/Composers/Bizet

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  • From Ben Bacarisse@21:1/5 to wij on Mon Mar 25 13:39:27 2024
    wij <wyniijj5@gmail.com> writes:

    On Mon, 2024-03-25 at 09:43 +0100, Fred. Zwarts wrote:
    ...
    1.0 = 3*(1/3) = 3*0.33333... = 0.99999...
    ...
    If not (if there is a difference), which number expresses the difference
    between 1.0 and 0.99999... ?

    Let a=0.999..., b=1, c=(a+b)/2, c is the number between a and
    b. (dense property)

    Since you have not yet taken even the first step in defining your
    numbers you have the luxury of pretending that (a+b)/2 might be anything
    you'd like it to be. But the computational processes you want to
    represent numbers don't permit what you are imagining. If + and / are
    defined as processes on infinite strings then with a=0.999... and b=1

    c=(a+b)/2 = 0.999... = a.

    Stop pretending and do the work. (1) Define your numbers. (2) Define
    =, +, -, * and / on them and only /then/ start telling the world that
    they have been wrong for centuries.

    --
    Ben.

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  • From Ben Bacarisse@21:1/5 to wij on Mon Mar 25 13:15:20 2024
    wij <wyniijj5@gmail.com> writes:

    On Mon, 2024-03-25 at 10:24 +0000, Ben Bacarisse wrote:
    wij <wyniijj5@gmail.com> writes:

    +-------------+
    Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the >> >    string may contain a plus/minus sign or a point:

         <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ]
         <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>]
         <dstr2>::= { 0, <nzd> } <nzd>
         <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9)  // 'digit' varys depending
         on n-ary

    So neither 0 nor 10 are Fixed_point numbers.  OK.  That's going to limit >> the usefulness of these numbers.

    Good catch. I will fix these grammar things, latter.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point
    number. The string of digits of x may be infinitely long }

    That's ill-defined as there are two {0, <nzd>} parts in the grammar.  I
    think you intended only one of them to be permitted to be not finite.

    ditto

    (And as has been pointed out, this is not a model of set to the real
    numbers.  You need to choose a different name.)

    IMO, these all boil down to the question "what is number?".

    No, it boils down to what words are already taken for certain classes of number. You know this. You did not pick "real number" because you
    didn't know what it means. You picked it because you did know and you
    wanted to imply that everyone else has been using it wrongly.

    I find it
    better (so far) to define 'number' on symbols and the associated ops.

    That is fine way to do things but you have not even taken the first step
    since your definition excludes 10.

    Because I feel computation (TM, algorithm,program,..) can and should
    be a large part of the basics of mathematics. E.g. I feel infinity may
    be nothing but a manifest of procedural loop. (This article tries to
    grasp this kind of idea https://sourceforge.net/projects/cscall/files/MisFiles/logic_en.txt/download )

    As usual, you don't really care about the details, do you?  It's all
    about looking technical rather than being precise.

    “Premature optimization is the root of all evil”

    Getting your base definition right so that it includes 0 as a number is
    not and optimisation and it would not be premature. Telling people they
    have been using the wrong concept of "real number" when you can can't
    even get the basic syntax right for your proposed alternative is
    premature publication.

    --
    Ben.

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  • From Richard Damon@21:1/5 to wij on Mon Mar 25 19:43:58 2024
    On 3/25/24 7:54 AM, wij wrote:
    On Mon, 2024-03-25 at 07:14 -0400, Richard Damon wrote:
    On 3/25/24 5:11 AM, wij wrote:
    On Mon, 2024-03-25 at 09:43 +0100, Fred. Zwarts wrote:
    Op 25.mrt.2024 om 01:53 schreef wij:
    On Mon, 2024-03-25 at 01:09 +0100, immibis wrote:
    On 25/03/24 00:05, wij wrote:
    On Sun, 2024-03-24 at 23:35 +0100, immibis wrote:
    On 24/03/24 15:59, wij wrote:
    The purpose this text is for establishing the bases for computational algorithm.
    This file
    https://sourceforge.net/projects/cscall/files/MisFiles/RealNumber-en.txt/download
    may be updated anytime.

    +-------------+
    Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the
           string may contain a plus/minus sign or a point: >>>>>>>>>
             <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ] >>>>>>>>>          <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>]
             <dstr2>::= { 0, <nzd> } <nzd>
             <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9)  // 'digit' varys depending on n-ary

           Two n-ary fixed-point number x,y are equal iff their form as mentioned above
           are identical.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point number. The string
           of digits of x may be infinitely long }

           Note: This definition implies that repeating decimals are irrational number.

    So the RATIO of 1 and 7 isn't RATIOnal?

    All rationals p/q are representable by q-ary fixed-point number. >>>>>>>

    0.99999... is representable by the following 10-ary fixed-point number: 1.0.

    How?

    1.0 = 3*(1/3) = 3*0.33333... = 0.99999...

    What is that? Refutation by assertion?

    If not (if there is a difference), which number expresses the difference >>>> between 1.0 and 0.99999... ?

    Let a=0.999..., b=1, c=(a+b)/2, c is the number between a and b. (dense property)


    But the density property requires a and b to be DIFFERENT numbers before
    it asserts that there is a number between them, otherwise c is just the
    same number as a and b.

    The premise of this thread said "If not" (means IF 0.999...!=1)


    False premise -> Unsound conclusions.

    If you want 0.999(9) to be different than 1.00 you need to move beyond
    the Real Numbers into some form of extended Reals, and understand what
    that does to what logic you can use.

    If going into some alternate or extended number system IS your goal,
    then you shouldn't call your numbers "The Reals", as that name is taken.

    --- SoupGate-Win32 v1.05
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  • From Richard Damon@21:1/5 to wij on Mon Mar 25 23:03:53 2024
    On 3/25/24 10:52 PM, wij wrote:
    On Mon, 2024-03-25 at 19:43 -0400, Richard Damon wrote:
    On 3/25/24 7:54 AM, wij wrote:
    On Mon, 2024-03-25 at 07:14 -0400, Richard Damon wrote:
    On 3/25/24 5:11 AM, wij wrote:
    On Mon, 2024-03-25 at 09:43 +0100, Fred. Zwarts wrote:
    Op 25.mrt.2024 om 01:53 schreef wij:
    On Mon, 2024-03-25 at 01:09 +0100, immibis wrote:
    On 25/03/24 00:05, wij wrote:
    On Sun, 2024-03-24 at 23:35 +0100, immibis wrote:
    On 24/03/24 15:59, wij wrote:
    The purpose this text is for establishing the bases for computational algorithm.
    This file
    https://sourceforge.net/projects/cscall/files/MisFiles/RealNumber-en.txt/download
    may be updated anytime.

    +-------------+
    Real Number |
    +-------------+

    n-ary Fixed-Point Number::= Number represented by a string of digits, the
            string may contain a plus/minus sign or a point: >>>>>>>>>>>
              <fixed_point_number>::= [-,+] <dstr1> [ . <dstr2> ]
              <dstr1>::= <nzd> [{ 0, <nzd> } <nzd>] >>>>>>>>>>>           <dstr2>::= { 0, <nzd> } <nzd>
              <nzd> ::= (1, 2, 3, 4, 5, 6, 7, 8, 9)  // 'digit' varys depending on n-
    ary

            Two n-ary fixed-point number x,y are equal iff their form as mentioned
    above
            are identical.

    Real Nunmber(ℝ)::= {x| x is represented by n-ary fixed-point number. The string
            of digits of x may be infinitely long }

            Note: This definition implies that repeating decimals are irrational
    number.

    So the RATIO of 1 and 7 isn't RATIOnal?

    All rationals p/q are representable by q-ary fixed-point number. >>>>>>>>>

    0.99999... is representable by the following 10-ary fixed-point number: 1.0.

    How?

    1.0 = 3*(1/3) = 3*0.33333... = 0.99999...

    What is that? Refutation by assertion?

    If not (if there is a difference), which number expresses the difference >>>>>> between 1.0 and 0.99999... ?

    Let a=0.999..., b=1, c=(a+b)/2, c is the number between a and b. (dense property)


    But the density property requires a and b to be DIFFERENT numbers before >>>> it asserts that there is a number between them, otherwise c is just the >>>> same number as a and b.

    The premise of this thread said "If not" (means IF 0.999...!=1)


    False premise -> Unsound conclusions.

    If you want 0.999(9) to be different than 1.00 you need to move beyond
    the Real Numbers into some form of extended Reals, and understand what
    that does to what logic you can use.

    If going into some alternate or extended number system IS your goal,
    then you shouldn't call your numbers "The Reals", as that name is taken.

    'real number' is already there. e.g. 'a line' or just a series of digits, whatever had practically used world wide now and then.
    Your 'real number' is also a theory which also suffers from revision.
    If you need a specific number system, you should name it otherwise.


    So, you are AGREEING that the term "Real Number" is already in use and
    that your attempts to "redefine" it is thus just an attempt to be
    confusiong?

    Maybe you just don't understand how much actual Theory there is behind
    the term "The Real Number System"?


    It seems you are becoming schizophrenic.

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